docs(readme); update maven dependency

Author: jzheng2017

README.md

@@ -98,7 +98,7 @@ Latest official release:
 <dependency>
   <groupId>nl.jiankai</groupId>
   <artifactId>spotify-web-api-wrapper</artifactId>
-  <version>1.3.0</version>
+  <version>1.4.0</version>
 </dependency>
 ```